Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 2]
Exam
Concepts Of Physics MCQ Edition [Volume 2]
Subject
Physics
Chapter
Bohr's Model and Physics of the Atom

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Bohr's Model and Physics of the Atom

Assume that under specific conditions, hydrogen atoms are permitted...

Assume that under specific conditions, hydrogen atoms are permitted to undergo only those transitions where the principal quantum number nn changes by 22. Determine the smallest wavelength emitted by hydrogen.

Options

  1. A121 nm121 \text{ nm}
  2. B103 nm103 \text{ nm}
  3. C487 nm487 \text{ nm}
  4. D91 nm91 \text{ nm}

Correct answer

B. 103 nm103 \text{ nm}

Step-by-step solution

The wavelength of the emitted photon is given by the Rydberg formula:

\dfrac{1}{\lambda} = R \left(\dfrac{1}{n_1^2} - \dfrac{1}{n_2^2} \right)

For the smallest wavelength, the energy difference between the transition levels must be maximum. Given the condition that the principal quantum number changes by 22, we have n2−n1=2n_2 - n_1 = 2. The maximum energy difference occurs for the lowest possible values of n1n_1 and n2n_2.

Thus, the transition is from n2=3n_2 = 3 to n1=1n_1 = 1.

Substituting these values into the formula:

\dfrac{1}{\lambda} =R \left(\dfrac{1}{1^2} - \dfrac{1}{3^2} \right) =R \left( 1 -\dfrac{1}{9} \right) = \dfrac{8R}{9}

λ=\lambda =\dfrac{9}{8R}

Using the standard value \dfrac{1}{R} \approx91.2 nm91.2 \text{ nm}:

λ=\lambda =\dfrac{9}{8} \times91.2 nm≈102.6 nm91.2 \text{ nm} \approx 102.6 \text{ nm}

The closest value among the given options is 103 nm103 \text{ nm}.
Practice Bohr's Model and Physics of the Atom on Quantrex Academy →

More from Bohr's Model and Physics of the Atom

The Bohr radius is given by a_0 = (ε_0 h^2)/(π m e^2) . Determine the dimensions of the… Concepts Of Physics MCQ Edition [Volume 2]Determine the wavelength of the radiation emitted by hydrogen during the transition from… Concepts Of Physics MCQ Edition [Volume 2]Determine the smallest wavelength of radiation that can be emitted by hydrogen. Concepts Of Physics MCQ Edition [Volume 2]Determine the wavelength of the radiation emitted by hydrogen during the transition from… Concepts Of Physics MCQ Edition [Volume 2]Determine the wavelength of the radiation emitted by hydrogen during the transition from… Concepts Of Physics MCQ Edition [Volume 2]Determine the smallest wavelength of radiation that can be emitted by He^+ . Concepts Of Physics MCQ Edition [Volume 2]Determine the smallest wavelength of radiation that can be emitted by Li^ ++ . Concepts Of Physics MCQ Edition [Volume 2]Calculate the Rydberg constant by substituting the values of the fundamental constants… Concepts Of Physics MCQ Edition [Volume 2] Full Bohr's Model and Physics of the Atom list All Concepts Of Physics MCQ Edition [Volume 2] PYQs